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Bug 514771

Summary:	build curl with c-ares support
Product:	[Fedora] Fedora	Reporter:	seth vidal <svidal>
Component:	curl	Assignee:	Kamil Dudka <kdudka>
Status:	CLOSED RAWHIDE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	low
Version:	rawhide	CC:	daniel, kdudka, tcallawa
Target Milestone:	---
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	7.19.6-11.fc13	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2009-10-01 07:28:39 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description seth vidal 2009-07-30 17:17:07 UTC

Doing some work on curlgrabber I noticed this in the curl docs:

from:
http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTNOSIGNAL
"If this option is set and libcurl has been built with the standard name resolver, timeouts will not occur while the name resolve takes place. Consider building libcurl with c-ares support to enable asynchronous DNS lookups, which enables nice timeouts for name resolves without signals. "

C-ares is in fedora and the license is compatible to curl. Consider rebuilding curl with --enable-ares=/some/path

Comment 1 Kamil Dudka 2009-08-04 08:26:23 UTC

Good idea. I'll try to build it in rawhide. The only thing I am not 100% sure for now, is the state of IPv6 support in c-ares.

Comment 2 Kamil Dudka 2009-08-04 08:58:39 UTC

More precisely described here by Daniel Stenberg:
http://curl.haxx.se/mail/lib-2009-08/0014.html

Comment 3 Kamil Dudka 2009-08-05 09:04:05 UTC

Seth, how much does it hurry? We have actually alpha freeze for F-12 now and I am not sure if the timing is optimal for such change.

> http://curl.haxx.se/mail/lib-2009-08/0014.html  

Going through the above mentioned thread you can see there were *some* problems when curl was switched to c-ares in Debian one year ago. But we have no details from Debian maintainers so far.

Comment 4 seth vidal 2009-08-05 12:26:39 UTC

Kamil,
 after looking through the problems, I figure holding off is probably a good idea.

However, maybe it is worth a try once rawhide opens up for f13.

thanks

Comment 5 Kamil Dudka 2009-10-01 07:28:39 UTC

Built as libcurl-7.19.6-11.fc13.

Comment 6 seth vidal 2009-10-01 13:51:41 UTC

Kamil,
 Thanks!

Comment 7 Kamil Dudka 2020-11-02 17:11:35 UTC

Rebuilding curl against c-ares introduced a lot of bugs (or missing features) that appeared worse than the previous signal handling issues:

    bug #548269
    bug #554305

Long story short, c-ares completely bypasses glibc's NSS (Name Service Switch), which causes curl to ignore system configuration and resolve host names differently than other programs running on the same system.

The signal handling issues were later resolved by switching curl to use a threaded DNS resolver, which is now available even in RHEL-7:

    https://src.fedoraproject.org/rpms/curl/c/438cbdbe